I'm not sure you understand how the profiles system works - you don't 'tweak their tweaks'... You aren't supposed to touch your profile, and it is also not something that changes just every day... you change it when you upgrade to a newer sabayon version - and yes, you CAN sometimes expect to need to fix things when you upgrade. It isn't as if right now you can just emerge -auDvN world even after a clean install, w/o some fixing...
And even so, the profile provides just the basis for your system - it doesn't override stuff youve explicitly put in your configs. you dont need to 'undo' anything... (you might have to do a thing or two when you first change the profile however - but when gentoo 2007.1 or 2008.0 comes, youll also need to do this if youll be using a gentoo profile)
Sabayon devs think they need to mask one of the packages for some reason. I see that that mask is deprecated as packages do in fact emerge and work fine now, so I need to put an entry in my package.unmask : <=category/thatmaskedpackage-version. Notice that I need to keep en eye on version of that package and if I simply add 'category/thatmaskedpackage' I'm already asking for trouble.
How is this different from what goes on today? you are (probably) on the ~x86 tree anyway which means that keyworded packages are emerged by default.. and as for masked packages, youre right about asking for trouble - and you probably also don't want to .unmask all future versions anyway, so what's your point?
What if there in fact comes a new version of that package which break everything badly? Which gentoo devs mask but *I* unmask by that entry in my config files. emerge -pvND world won't catch these and I'll notice something only when some reverse dependency of that package won't compile or don't run.
If *you* unmask something, it is your responsibility to see that it doesn't break your system - again, how is this different from today's situation?[/quote]